Fastening systems for assembly components of an underwater vessel are known in the prior art. Some of these aforementioned systems can incorporate a pair of hemispherical clamps, which can be used to mate adjacent body segments. The hemispherical clamps can extend approximately 178 degrees around the circumference of the hull, and the clamps can be placed around a single O-ring and tightened to function as the sealing mechanism for adjacent vessel segments.
But single O-ring type systems of the type described above can have several disadvantages. First of all, these types of systems can be subject to single point failure, which could cause loss of investment of the contents of the vessel or the vessel itself. Additionally, the prior art systems can be challenging to install, as the two clamps do not meet face to face, but instead have a two degree gap between them for adjustment and tolerance variability. Installation is also made more challenging because of their necessarily tight fit. Because of the required tight fit, the clamps must be pressed on sometimes with the help of a mallet, which can make it very difficult to maintain symmetric gaps between front and back clamps.
Another issue with the aforementioned gap is the challenge of maintaining equal gap front and back as the screws are tightened. Consistency in the gap is needed for the mating fasteners to tighten properly. If the gap is inconsistent, the clamp's mating fasteners may not able to be torqued due to the gap and mirrored screw geometry. When tightened, the screws fight each other for tension. With an uneven gap, as one screw is tightened the other loosens negating any torque value. This gap is also utilized during removal where a rod or screwdriver is inserted into the gap and struck with a mallet to force the clamps off. Both the clamps and the vessels can be damaged during the removal process.
One way to solve the above problems could be to use a standard Marmon clamp to mate the two adjacent segments. But Marmon clamps can also produce additional disadvantages, such as non-compact design, difficult mating, and protruding features which could increase the hydrodynamic draft of the overall vessel, and which could also snag objects along the outside of a moving UUV (pressure vessel).
In view of the above, it is an object of the present invention to provide a pressure vessel clamping device that allows for mating of segments in a manner which keep the outside diameter consistent along its length, for increase hydrodynamic efficiency during deployment, operation and retrieval. Another object of the present invention is to provide a pressure vessel clamping device that provides increased higher reliability of the watertight seal. Another object of the present invention is to provide a pressure vessel clamping device that provides for a consistent gap forward and back to prevent uneven gap and iteration of assembly. Yet another object of the present invention to provide a pressure vessel clamping device that maintains a consistent gap size during assembly, and which provides a resistance that allows the mating fasteners to be torqued during assembly. Still another object of the present invention to provide a pressure vessel clamping device that can be easily and quick assembly and disassembly of pressure vessel segments. Yet another object of the present invention to provide a pressure vessel clamping device that allow for disengagement of the clamping device without damaging the device or the pressure vessel segments. Another object of the present invention to provide a pressure vessel clamping device which can be easy to manufacture, and which can be used in a cost-efficient manner.